1. Field of the Invention
This invention relates to therapeutic temperature regulation and, particularly, to controlling shivering during maintenance of normothermia or induced hypothermia.
2. Description of Related Art
Therapeutic induction of hypothermia and therapeutic maintenance of normothermia are used to protect at-risk brain tissue from secondary injury in the setting of anoxic brain injury after cardiac arrest and other central nervous system pathologies. A major limiting factor in the induction of hypothermia or maintenance of normothermia is the generation of shivering, which is a normal adaptive physiologic response that serves to bring the body temperature upwards. In addition, shivering in this context can have harmful physiological effects by diverting energy away from the critical organs such as the brain and heart.
Continuous counterwarming measures ((“passive”) counterwarming) have been found to have some degree of efficacy in treating shivering. When shivering is observed by attending medical personnel, an assessment is made by the personnel and, if judged to be indicated, a counterwarming therapy may be employed, for example by deploying a warming blanket onto or beneath the patient. Conventionally, passive counterwarming once applied is not adjusted over the therapeutic course.
Other anti-shivering measures in common use include pharmaceuticals; currently available options have limited efficacy and may have serious adverse effects, and the modes of administration may pose risks to the patient.